From: "François Dumont" <frs.dumont@gmail.com>
To: Ken Matsui <kmatsui@cs.washington.edu>, libstdc++@gcc.gnu.org
Cc: gcc@gcc.gnu.org
Subject: Re: [GSoC] Conflicted Built-in Trait Name
Date: Mon, 27 Mar 2023 19:33:49 +0200 [thread overview]
Message-ID: <e15b6e8a-a9fd-d1d9-c2f9-b8b92bd5110a@gmail.com> (raw)
In-Reply-To: <CAML+3pWAkPvAFELtpAiJFK5amXV7QA17WGja7W45cbGLub5Ntw@mail.gmail.com>
On 26/03/2023 04:01, Ken Matsui via Libstdc++ wrote:
> On Sat, Mar 25, 2023 at 5:38 AM Marc Glisse <marc.glisse@inria.fr> wrote:
>> On Sat, 25 Mar 2023, Ken Matsui via Gcc wrote:
>>
>>> Built-in trait naming simply adds two underscores (__) to the original
>>> trait name. However, the same names are already in use for some
>>> built-in traits, such as is_void, is_pointer, and is_signed.
>>>
>>> For example, __is_void is used in the following files:
>>>
>>> * gcc/testsuite/g++.dg/tm/pr46567.C
>> This is a testcase, you can rename __is_void to whatever in there, it
>> doesn't matter.
>>
>>> * libstdc++-v3/include/bits/cpp_type_traits.h
>> This __is_void seems to be used in a single place in
>> include/debug/helper_functions.h, couldn't we tweak that code so __is_void
>> becomes unused and can be removed?
> That worked. Thank you!
What worked ?
>
> So, we can remove a code in a header as long as it is not standard and
> is not used elsewhere, can't we?
You can do anything you like as long as you run the testsuite before
presenting your patch. Here note that you'll need to run:
make check-debug
to run tests in _GLIBCXX_DEBUG mode which is making use of the code in
helper_functions.h.
Clearly this usage of std::__is_void could be replaced with your builtin
by reimplementing _Distance_traits like this:
template<typename _Iterator,
typename = typename std::__is_integer<_Iterator>::__type>
struct _Distance_traits
{
private:
typedef
typename std::iterator_traits<_Iterator>::difference_type _ItDiffType;
typedef
typename std::conditional<__is_void<_ItDiffType>,
std::ptrdiff_t, _ItDiffType>::type _DiffType;
public:
typedef std::pair<_DiffType, _Distance_precision> __type;
};
this is untested, just to give you an idea of what your patch could be.
François
next prev parent reply other threads:[~2023-03-27 17:33 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-25 7:53 Ken Matsui
2023-03-25 12:23 ` Roy Jacobson
2023-03-27 21:58 ` Jonathan Wakely
2023-03-27 22:48 ` Ken Matsui
2023-03-25 12:38 ` Marc Glisse
2023-03-26 2:01 ` Ken Matsui
2023-03-27 17:33 ` François Dumont [this message]
2023-03-27 20:16 ` Ken Matsui
2023-03-27 21:43 ` Jonathan Wakely
2023-03-27 21:49 ` Jonathan Wakely
2023-03-27 21:55 ` Ken Matsui
2023-03-28 21:29 ` Ken Matsui
2023-03-28 23:24 ` Jonathan Wakely
2023-03-28 23:33 ` Ken Matsui
2023-03-30 5:11 ` François Dumont
2023-03-30 8:33 ` Ken Matsui
2023-03-30 12:23 ` Jonathan Wakely
2023-03-30 18:44 ` Ken Matsui
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